Cheers to hot barley

Aussies love barley – after all, it makes beer – and an international team of researchers has good news for its production in Australia. Barley typically struggles to grow in a hot country like ours, but the team has identified a new mechanism that allows the grass to grow more flowers, and therefore grains, despite rising temperatures.

The researchers, led by Gang Li of the University of Adelaide and Dabing Zhang of the University of Adelaide and Shanghai Jiao Tong University, China, demonstrated that removing a protein called HvMADS1 made barley branch out and grow more flowers at high temperatures.

“Cereal crops such as wheat and barley are worth over $12 billion to the Australian economy,” says Li.

“Genes that control the amount of grain produced per plant under higher temperatures are really attractive targets for breeders and researchers, particularly in the face of changing environmental conditions.

“It has long been presumed that environmental cues such as temperature are responsible for the diversity of the biological structures between cereals. However, the mechanisms behind the structural changes have been largely unknown, which is why this study is important.”

Read more: Wheat and barley are incredibly diverse

Like other grasses, barley grows flowers that get pollinated and produce seeds. These seeds are grains that we use to eat and make beer.

In the study, published in Nature Plants, the team found that HvMADS1 regulated the number of  flowers growing on each ‘spike’, the section of the reproductive part of the barley that is equivalent to a corn cob.

Normally, these spikes will branch out and make lots of seeds, but the team found that when it gets too hot, HvMADS1 bound with other factors that stopped the branching, leading to fewer branches and fewer grains.

Thankfully, the researchers figured a way to reverse this. Using CRIPSR-Cas9, the team was able to remove functional HvMADS1, and the altered barley was once again able to branch out and grow more flowers, despite the heat.

“This could ultimately result in the production of more grain per plant,” says Li.

Interestingly, there may be other HvMADS proteins that could be used.

“This study reveals a new role of this protein family in responding to thermal change and directing the composition of flowers on a stem,” says co-author Matther Tucker of the University of Adelaide.

“With short to medium temperature rises predicted globally, plant scientists and breeders have an enormous challenge ahead of them to generate crop yields needed to feed growing populations in higher temperatures.

“By having a better understanding of the genes underpinning desirable plant traits in response to temperature, scientists can offer insights into breeding climate-smart plants to sustain productivity.”

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